Google said it uncovered a China-borne cyber attack that targeted the personal email accounts of high-level individuals, including U.S. government officials, military personnel and Chinese political activists.

The campaign successfully nabbed passwords for hundreds of Gmail accounts, in an apparent effort to monitor the email content of specific people. Journalists and officials in several Asian countries, predominantly South Korea, were also targeted. The company said the assault appeared to originate in Jinan, China.

The revelation follows a similar effort early last year that infiltrated the accounts of human rights advocates and prompted the Mountain View Internet giant to relocate its search operations from mainland China.

Then, as now, Google stopped short of accusing the Chinese government of orchestrating or encouraging the security breach, but the victims of the attacks obviously raised that question.

The company didn’t specify what kind of information was actually accessed. Affected accounts have been secured and the victims have been notified, as have government authorities, it said.

The recent campaign was different from last year’s in at least one notable way: The attack doesn’t appear to have targeted Google’s systems directly.

Instead, the company said the orchestrators likely sought access to the accounts through so called phishing schemes, in which hackers try to trick people into revealing their passwords and other details by appearing to come from a trusted source.

“It’s important to stress that our internal systems have not been affected — these account hijackings were not the result of a security problem with Gmail itself,” the company said. “But we believe that being open about these security issues helps users better protect their information online.”

Google stressed the importance of users taking online security seriously, suggesting they enable two-step verification for their accounts and use strong passwords.